In view of the extreme expensiveness and unstable supply of natural musk obtained from a musk deer, works have been undertaken intensively from old times to develop compounds having musk-like tone of fragrance and a large number of compounds have been discovered including those belonging to the types of nitro-musks, indan musks, Tetralin musks, macrocyclic musks and the like.
In recent years, however, several of these compounds have become banned for use in soaps, cosmetics and the like in respect of the safety concern. Therefore, it is desired to have advent of a compound having musk-like tone of fragrance but less problems in safety. As such a compound, compounds having a skeleton of cyclopentanaphthalene are known and disclosures are already given for ##STR2## in German Pat. No. 2,114,216 and for ##STR3## in Japanese Patent Publication 42-6491 while they are each not satisfactory in respect of the quality and strength of the fragrance although they have no problem in respect of safety.
Accordingly, the object of the present invention is to provide a compound of musk-like fragrance having a skeleton of cyclopentanaphthalene with high safety, low costs for manufacturing and fragrance excellent in both of quality and strength.